Ionisation energies

Barium is in Group 2 of the periodic table.

Which statement(s) about barium is / are correct?

1 Its outer shell electrons are in an s-orbital.

2 It reacts more vigorously with water than magnesium.

3 It has a higher first ionisation energy than magnesium.

A 1, 2 and 3

B Only 1 and 2

C Only 2 and 3

D Only 1

This question is about trends in the periodic table.

The graph shows the melting points for Period 3 elements from sodium to silicon.

Complete the graph to show approximate melting points for P, S, C l and Ar.

Explain why silicon has a higher melting point than aluminium.

Use ideas about structure and bonding in your answer.

The table shows the first ionisation energies for the elements in Period 3.

Write an equation to represent the first ionisation energy of sulfur. Include state symbols.

The table shows that there is a general increase in first ionisation energies across Period 3, but that this trend is not followed by phosphorus to sulfur.

Explain why the first ionisation energy of sulfur is lower than the first ionisation energy of phosphorus.

A student adds an aqueous solution of bromine, Br₂(aq), to two test tubes.

The student adds aqueous sodium iodide, NaI(aq), to the Br₂(aq) in one test tube, and aqueous sodium chloride, NaCl (aq), to the Br₂(aq) in the other test tube.

Complete the table to show the student's observations.

Write ionic equation(s) for any reaction(s) that take place.

Ionic equation(s)........

* The hydrides of silicon, phosphorus and sulfur have simple molecular structures, but their molecules have different shapes.

Explain why molecules of SiH₄, PH₃ and H₂S have different shapes.

Your answer should include ‘dot-and-cross’ diagrams (outer shells only), the names of the shapes and an explanation of why the bond angles are different.

Which element has the largest third ionisation energy?

Your answer

This question is about energy changes.

Lattice enthalpies can be determined indirectly using Born-Haber cycles.

The table below shows the energy changes that are needed to determine the lattice enthalpy of barium iodide, BaI₂.

The diagram below shows an incomplete Born-Haber cycle that can be used to calculate the lattice enthalpy of barium iodide.

On the dotted lines, add the species present, including state symbols.

Ba²⁺(g) + 2I(g) + 2e^–

Calculate the lattice enthalpy of barium iodide.

lattice enthalpy =........ kJ mol^–1

The first and second ionisation energies of magnesium, Mg, and strontium, Sr, in Group 2 are given in the table below.

• Explain why the first ionisation energy of Mg is greater than the first ionisation energy of Sr.

• Explain why the second ionisation energy of Sr is greater than the first ionisation energy of Sr.

The three elements that, when in a molecule, can form hydrogen bonds with other suitable molecules.

An element that is a solid at RTP with a simple molecular lattice structure.

The two elements with atoms containing five unpaired electrons.

The element in Period 3 that exists in the solid state as a network of atoms bonded by strong covalent bonds.

The p-block element in Period 3 that forms a compound with fluorine with octahedral molecules.

The element that forms 1– ions most readily.

The element with an average atomic mass of 1.244 10^–22 g.

The graph shows the first ionisation energies for elements from helium, He, to boron, B, in the periodic table.

Complete the graph for C, N, O, F and Ne.

Explain why the first ionisation energies of He and Be are both higher than the first ionisation energy of Li.

Explanation for He:........

Explanation for Be:........

Explain why the first ionisation energy of Be is higher than the first ionisation energy of B.

Which row shows elements in order of increasing first ionisation energy?

A Ca < Si < P < N

B N < P < Si < Ca

C Ca < N < P <Si

D C < Si < P < Ca

Your answer

This question is about magnesium and magnesium halides.

Magnesium has metallic bonding and is a good conductor of electricity.

Describe, with the aid of a labelled diagram, the metallic bonding in magnesium and explain why magnesium conducts electricity.

Include the correct charges on the particles in your diagram.

The 12 successive ionisation energies of magnesium are shown in Table 16.1.

Write an equation to represent the fourth ionisation energy of magnesium.

Include state symbols.

Explain how the successive ionisation energies provide evidence that magnesium is in Group 2 of the periodic table.

Electrons occupy orbitals.

In Table 16.2 below, add a tick (✓) below the ionisation numbers that are responsible for removing an electron from a full orbital in a magnesium atom.

The enthalpy change of solution for magnesium fluoride, MgF₂, can be determined indirectly using an energy cycle based on the enthalpy changes below.

Explain what is meant by enthalpy change of solution.

Calculate the enthalpy change of solution of MgF₂.

enthalpy change of solution =........ kJ mol^–1

Which set of elements in the solid state contain a simple molecular lattice, a giant covalent lattice and a giant metallic lattice?

A S, Si, A l

B P, Si, C

C S, P, Si

D Mg, P, S

Your answer

Sir Humphry Davy discovered several elements including sodium, potassium, magnesium, calcium and strontium.

Explain which block in the Periodic Table sodium and magnesium belong to.

A sample of magnesium, A_r= 24.305, is found to consist of three isotopes. The accurate relative isotopic masses and % abundances of two of the isotopes are shown in the table.

Determine the relative isotopic mass of the third isotope of magnesium in the sample.

Give your answer to 5 significant figures.

A student adds an excess of calcium oxide to water in a test tube. In a separate test tube, the student adds an excess of strontium oxide to water.

Write the equation for the reaction of calcium oxide with water.

State symbols are not required.

Suggest the approximate pH of the two solutions formed in the test tubes.

pH with calcium oxide........

pH with strontium oxide........

The table below shows enthalpy changes involving potassium, oxygen and potassium oxide,

The incomplete Born–Haber cycle below can be used to determine the lattice enthalpy of potassium oxide.

In the boxes, complete the species present in the cycle. Include state symbols for the species.

Calculate the lattice enthalpy of potassium oxide.

lattice enthalpy =........ kJ mol⁻¹

A similar Born–Haber cycle to potassium oxide in (d) can be constructed for sodium oxide.

The first ionisation energy of sodium is more endothermic than that of potassium.

Explain why.

The lattice enthalpy of sodium oxide is more exothermic than that of potassium oxide.

Explain why.

Which statement best explains why nitrogen has a larger first ionisation energy than oxygen?

A N atoms have less repulsion between p-orbital electrons than O atoms.

B N atoms have a smaller nuclear charge than O atoms.

C N atoms lose an electron from the 2s subshell, while O atoms lose an electron from the 2p subshell.

D N atoms have an odd number of electrons, while O atoms have an even number.

Your answer

Select an element from the first three periods that fits each of the following descriptions.

The element that forms a 1– ion with the same electron configuration as helium.

The element with the highest first ionisation energy.

The element in Period 3 which has the successive ionisation energies shown below.

The element which forms a compound with fluorine that has octahedral molecules.

An element which reacts with water to form an acidic solution.

The element X, which forms a compound with hydrogen, XH₃, with a molar mass of 34.0 g mol^–1.

An element which forms a compound with hydrogen in which the element has an oxidation number of –4.

The element which has a density of 1.33 × 10^–3 g cm^–3 at room temperature and pressure.

Table 1.1 shows some properties of Period 3 chlorides.

Explain the properties shown in Table 1.1 in terms of bonding and structure.